Contraction joint assembly



Patented Feb. 22, 1949 CONTRACTION JOINT ASSEMBLY Alan E. Brickman, Worcester, Mass, assignor to The American Steel and Wire Company of New Jersey, a corporation of New Jersey Application December 12, 1946, Serial No. 715,715

3 Claims.

This invention relates to a contraction joint assembly and more particularly to such a joint used without a center parting strip. Transverse contraction joints are assembled and pinned to the sub-grade between the forms ahead of the mixing, spreading and finishing machine. The wet concrete is dumped within the forms and the spreader machine forces it forward toward the tranverse joints. In some cases it is necessary to use bulkhead plates to prevent the load carrying dowels in the joint assembly from moving out of parallelism with one another. During subsequent removal of these bulkheads the concrete around the joints may be damaged and it is therefore desirable to eliminate their use. With some types of joints used at present it is necessary to use connecting wires across the slab separation which takes place when the pavement contracts, the wires having the disadvantage of restraining this action until they finally break.

It is an object of my invention to provide a joint which can withstand the pressure of the wet concrete without the use of bulkheads or tie wires.

Another object is to provide a joint assembly which allows the concrete to come in direct contact with the majority of the dowel surface, thus forming a long socket for the dowel in the concrete.

Still another object is to provide a joint assembly for supporting the load transfer dowels in parallel relationship with respect to the grade and lengthwise of the pavement in a manner which re'strains the secured assembly from movement under the flow of the wet concrete.

These and other objects will be more apparent after referring to the following specification and attached drawings, in which: Y

Figure 1 is a plan view of the assembly;

Figure 2 is a side view of Figure 1; and

Figure 3 is a setional view of the joint assembly.

Referring more particularly to the drawings, the reference numeral 2 indicates the sub-grade on which the contraction joint assembly is supported. A plurality of load supporting dowels 4 are arranged in a manner to extend across a contraction separation 6 between concrete slabs 8 and Ill. The means for supporting the dowels 4 are the same on each side of the contraction separation '6 and consists of a sand plate angle I2 extending longitudinally of the contraction separation 6 and a spacer rod I4 parallel to the angle I2, the angle I2 and rod I4 being connected by a vertical rod I6 at each of the dowel rods 4. The top part of the rod I6 extends outwardly away from the contraction separation 6 and is arranged in the form of a helical coil I8 having a comparatively long pitch and a radial bend 2|] at its outer end extending inwardly toward the center of the coil. The internal diameter of the coil I8 is slightly less than that of the dowel rod 4 to provide a frictional grip thereon. For best functioning, the helical coil must extend completely around the dowel rod 4. The lower end of the rod I6 is bent and welded to the angle I2 while the spacer rod I4 is welded to the rod I6 in a position to help support and provide accurate spacing and parallelism to the dowel rods 4. Openings 22 are provided in the angle I2 to receive spikes 24.

In assembly, an angle I2 with its associated structure is arranged on each side of the contraction separation 6 and the dowel rods 4, which have been painted and greased over their entire length, are arranged in the helical coils I8 with their ends abutting the stops 20. The angles I2 are then fastened to the sub-grade 2 by means of the spikes 24 passing through the openings 22 after which the concrete is poured and a separating strip 26 is lowered into the upper portion of the concrete as shown in Figure 3. As contraction of the concrete occurs, a crack will form along the contraction separation 6, thus dividing the concrete into'two slabs 8 and I0. Since the dowels 4 are painted and greased, they move in the sockets provided by the concrete when the concrete expands and contracts.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the followin claims.

I claim:

1. In a transload device for transferring loads between adjacent slabs, the combination including a plurality of dowel members adapted to extend into both slabs, and a support embracing each end of the dowel members, said support comprising a resilient helical coil with the inner end projecting downwardly to form a support for the dowel and the outer end bent inwardly to form a stop for the dowel, the coil having spaced apart convolutions and the internal diameter thereof bein slightly less than ,the diameter of said dowel member to provide a frictional grip thereon.

2. In a transload device for transferring loads between adjacent slabs, the combination including a plurality of dowel members adapted to extend into both slabs, a support embracing each end of the dowel members, said support comprising a, resilient helical coil with the inner end projecting downwardly to form a support for the 7 3; In a-tran'sloact device for transferring loads between adjacent sl'abs, the combination including a dowel member adapted to extend into both 10 slabs, a support embracing one end of the dowel member, said support comprising a. resilient helicalcoil with the inner end projecting downwardly to form a support for the dowel-and the outer end bent inwardly to form a stop for the. dowel, the coil having spaced apart conyolutions and 4 the internal diameter thereof being slightly less than the diameter of said dowel member to provide a frictional grip thereon.

ALAN E. BRICKMAN.

REFERENCES CITED Theriollowing. referencesv are of record in the V file of this patent:

UNITED STATES PATENTS Number 7 Name Date 1,752,327 7 Briody Apr. 1, 1930 1,830,883- Nester NOV. 10, 1931 71,850,868 Drake Mar. 22, 1932 2,154,748 Hillberg- Apr. 18, 1939 2,208,454 Geyer et a1 July 16, 1940 

